The invention relates to a bearing element produced as an injection-moulded part made of an elastomer, which is a bearing element for upholstery in particular for rear-ventilated upholstery supports such as upholstery, mattresses or the like for seat or bed systems.
Upholstery supports serve as supports for upholstery, on which the human body (hereafter referred to as a xe2x80x9cbodyxe2x80x9d) can be placed in an ergonomically appropriate manner. Such type of upholstery is known from EP 0401 712, where the entire area of the support is covered with elastic elements, which is supported in U-profiles to avoid overloading and to limit the available spring deflection, so that for the placing of seats or bed systems the bearing surface for an upholstery support such as a mattressxe2x80x94as is already known from DE 36 12 603 A1xe2x80x94is divided into subareas, which are arranged in a regular patterns and where each individual one of these spring elements is designed to be spring-loaded.
Upholstery resting on surfaces absorbs body moisture and during a sitting or resting period gets wet, in particular in areas where people are resting in a humid atmosphere for lengthy periods and where the bearing surface is impermeable to moisturexe2x80x94such as for instance in caravans and in boats. To allow rear ventilation, EP 0 653 174 suggests to provide the bearing plate with openings. An unsatisfactory aspect of these proposals is that the height of the individual bearing elements must be (relatively) great, since the available range of spring deflection is only a fraction of the height of the unloaded bearing element.
A frame for seat or bed systems, whose longitudinal and transverse bars are provided with easily mountable spring elements is described in DE 196 37 933 C: where these spring elements have bearing plates on which the mattress or upholstery rests. The spring elements are defined by leaf spring elements in a lying arrangement, which leaf spring elements are almost C-shaped and are arranged mirror-symmetrically to one another in such a manner that the centre of the lower leaf spring is supported on the bar and the upper leaf spring supports the centre of the bearing plate.
GB 2 143 123 (corresponding to U.S. Pat. No. 4,688,893) describes a support for upholstery or the like, which support is movable within itself, and where a number of ring-shaped connecting members are connected with one another by means of clamping bodies. Such a support is stable within itself due to these interconnections and does not require an additional support, however the movability of the support within itself does not permit a force-related supporting adjustment. A different mattress support with an elastic top surface, made up of a plurality of foam rubber blocks is described in DE 196 00 434, which proposes the use of foam rubber blocks of varying degrees of hardness to achieve the hardness adjusted to the respective supported body region. Both these documents do not describe a support consisting of individual bearing elements with at least base and bearing plate.
Finally, DE 295 05 052 U (corresponding to U.S. Pat. No. 5,787,533) describes a bearing element, where a grid is formed of crossing pieces and webs, wherein, onto the crossing pieces and/or the webs, spring bodies are clipped, which spring bodies have bearing plates attached to their heads. In this instance the locking parts have different designs, a mere placing of the bearing plate onto the base is not possible.
It is therefore the object of the present invention to further develop the known bearing elements in such a way that the range of spring deflection consists of a substantial proportion of the total height, whereby with the rear ventilation maintained, the bearing elements are easy and economical to produce and have a wide range of applications; in addition, a bed system with such bearing elements shall be proposed which can be easily and economically produced and is of versatile use.
In order to achieve the spring action in a first embodiment, at least three or four bearing arms are provided which are directed outwardly from a base, which bearing arms are defined as leaf springs with a spring deflection aimed in the direction of the bearing pressure. Each of these bearing arms is provided with a terminal bearing surface; these bearing surfaces of a bearing element together form the bearing plate holding the upholstery, to which bearing plate they are fastened between the bearing surfaces in the region of bridging connections. When the springs are compressed, the bearing surfaces are forced outwardly. These bearing surfaces are coupled with further spring elements in such a manner that the outward movement loads these further spring elements. In this case, both springs act in the same direction. When the springs of the bearing arms are being loaded by being pressed down, the bearing plates moving outwardly cause a loading of the further spring element, so that ultimately the spring load-deflection curve of the bearing element can be set as required or as desired by the combination of both curves. The deflection of the bearing surfaces being possible down to the base, it is possible to achieve spring deflections whichxe2x80x94up to material thicknessxe2x80x94corresponds to the height of the bearing element itself.
These bearing arms have a rotationally symmetric arrangement, so that the angular distance of three bearing arms is 120xc2x0 and that of four bearing arms 90xc2x0. When the leaf springs forming the bearing arms are designed in such a way that their spring constants are equal, there results, also in lateral force components, a deflection without the xe2x80x9ccantingxe2x80x9d (known from other upholstery supports) so that a correct upholstery is obtained; it is however obvious that the spring constants are selected independently of this consideration. If, furthermore, by a corresponding design of the bearing surfaces, the bearing plate contains a free inner space, at least of the size of the base area, ranges of spring deflections can be achieved whichxe2x80x94apart from the material thicknessxe2x80x94correspond to the height of the bearing element itself, so that this deflection can even occur down to the plane of the base. In this case it is advantageous if the bearing arms supplying the spring force are made of a correspondingly high-quality elastomer and the bearing surfaces of an economical plastic material, which plastic parts can be produced by way of the two-component-injection moulding process or in separate production processes.
One advantageous embodiment proposes the use of undulated springs as spring elements in the bearing arms. The stretching of the bearing arms in this case leads to a compression of the undulated spring, resulting in counteracting the change of position of the bearing surface. The coupling spring elements in this embodiment are designed as Omega-type springs between the bearing surfaces which are divided, linking them. In particular the Omega design allows a spring deflection which is not reduced by undulations. By means of these further spring elements these bearing surfaces are coupled in such a manner that the outward movement results in a loading of these further spring elements. Both springs work in the same direction. If the springs of the bearing arms are loaded by downward pressure, the bearing plates moving outwardly cause a loading of the further spring elements so that ultimately the spring load-deflection curve of the bearing elements can be set by means of the combination of both spring load-deflection curves in such a way as is necessary or desirable.
In order to fasten these bearing elements on a support, the base is designed accordingly. If differences in height in the installation are to be adjusted in such a manner that all bearing plates are positioned in a plane, the base is advantageously defamed as a base plate or as a base body of corresponding height. In one embodiment the base plate/the base body is provided with a central hole. The fastening is performed by means of a screw or a dowel pin wherein the screw or dowel pin penetrate into the support. In a similar manner the base plate is provided with two holes or dowels which are diametrically opposite to each other relative to the centre of the base plate. Also in this cast the fastening is achieved by means of screws or dowel pins, the connection thus screwed or doweled is torsionproof due to its hole configuration.
If a T-shaped holder is fastened on the support, the central hole for secure fastening by overlapping of this holder has at least one, preferably however two flattened sides opposite each other. Due to the flattened sides, the T-shaped holder can be fixed to the support: the bearing element is then placed on top and fixed by a rotation of approximately 90xc2x0.
In a further embodiment, the base plate has hook-shaped laths: these laths interact with holding elements provided on the support in such a manner that the hook-shaped laths engage with corresponding projections at these holding elements and form a conjugate connection. If these hook-shaped laths are elongated and arranged on both sides of the centre of the base plate, they form one part of a sliding connection the other part of which defines the holding elements provided on the support so that the bearing elements can be slipped onto such holding elements: if the laths are arcuate and arranged diametrically opposite relative to the centre of the base plate, they define part of a twist-lock connection, the other part of which is defined by corresponding holding elements provided on the support. The bearing elements can be fastened to the holding elements in the manner of a bayonet-type twist-look connection. An advantageous design of the laths proposes the provision of stop means to limit the twist-lock or sliding range. Both these arrangements allow the bearing elements to be fixed in a simple and secure manner to the support, wherein the stop means allow for the fixing of the desired positioning.
In a second embodiment, the spring action is achieved by the bearing element having a spring body arranged between a foot mount and a bearing plate, wherein the foot mount has disposed on it one part of the look and the bearing plate the other part of the lock designed as means for the fixable and releasable insertion of the spring body as well as for the releasable attachment of the bearing plate onto the foot plate. The spring body itself has at one end the upper part of the locking means and at the other end the lower part of the locking means and can thus have one of its spring body ends placed on the base plate and its other spring body end attached to the bearing plate; base mount and bearing plate are placed at a greater distance from one another by being spaced apart by the spring body. In this way a spring-loaded bearing element is produced which, when provided with spring bodies of different heights, can be used at different heights and thus facilitate a height adjustment, wherein the height of the spring body determines the height of the bearing surface.
A flat bearing element is solely formed by the combination of a foot mount with a bearing plate placed on a support structure, which arrangement is joined together by means of locking means, advantageously as a bayonet-type twist-lock connection, where projections engage in recesses shaped as circle segments, and which are provided in the central part of the bearing plate and allow for twist-locking. The projections are advantageously defined as mushroom-shaped protrusions engaging in recesses behind the central part. Locking means are provided for this arrangement which interact by latching into place, and which are generally defined as lugs, protrusions or the like as well as corresponding recesses or indentations.
In one embodiment, the spring body between spring body foot and spring body head is defined by two double polygons, with their tips directed towards each other, whose outwardly directed surfaces form the spring body foot and the spring body head. The polygon tips directed towards each other are joined in such a way that they form between them a tube piece of essentially rectangular cross section, which acts as a spring tube and stabilises the polygon spring and, when compressed, forms a bearing with its own spring load-deflection curve. In a further embodiment the spring body is formed by a single polygon. Here the outer sides of the polygon form the foot plate or the spring body head, whilst the surfaces directed laterally outwardly define the tips directed outwardly. The inner side of the spring body head has a tube piece integrally formed with it whichxe2x80x94analogous to the tube spring in the double polygonsxe2x80x94define a semi-tube spring, which when compressed bears against the inner side of the spring body foot and thus forms a bearing with its own spring load-deflection course.
The bearing plate in one embodiment has at least three or four bearing arms directed outwardlyxe2x80x94each one running into an outer bearing surfacexe2x80x94and are arranged opposite each other. Furthermore, the bearing plate has an inner bearing surface, supported on the central plate. Radial connectors link the central plate to the outer bearing surfaces, wherein the outer bearing surfaces relative to the height of the inner bearing surfaces are arranged at a higher level. In a further development of this embodiment there are arranged in the bearing arms between each of the outer and inner bearing surfaces intermediate bearing surfaces, which are integrally formed with the radial connectors at a higher level than the inner bearing surface, but at a lower level than the outer bearing surfaces which are arranged at an inclined position. This stepped height variation results in an essential reduction of the contact area of the underside of the mattress or the like. The bearing surface is advantageously reinforced with bent off edge regions with C-shaped or U-shaped cross section of at least the outer bearing surfaces.
In order to adjust the deflection of the stepped bearing surfaces to the requirements, the radial connectors are defined as bridging elements linking the individual bearing surfaces, the rigidity of which bridging elements determines the necessary force required for the deflection. To adjust these forces to the requirements, these bridging elements are adjusted in width and thickness. In a preferred embodiment, these bridging elements are designed as spring members, wherein the spring members are preferably equipped with undulated springs as spring elements. The spring elements are adjustable to the desired or required force ratio by an appropriate design. In this design the ventilation is considerably improved, wherein it is advantageous, if independent therefrom the radial connectors and/or the bearing surfaces are provided with ventilation openings; in addition an improved accommodation of the physiological sleeping position is thereby achieved.
The one embodiment has three or four bearing arms at angular distances of 120xc2x0 or 90xc2x0: when several bearing elements are assembled with beaming plates into one upholstery support, these bearing arms of adjacent bearing plates can be positioned in such a manner that an (almost) continuous bearing surface is provided, in particular when the bearing arms are shaped accordingly. In three-arm bearing plates, the bearing plates are placed at a xe2x80x9cturned overxe2x80x9d arrangement, so that in each case two bearing arms of the one bearing plate engage with a bearing arm of the adjacent bearing arm. When four bearing arms are used, these are positioned advantageously on a grid as support structure, in such a manner that the lath is xe2x80x9cinclinedxe2x80x9d relative to the crossed bearing arms.
In an advantageous further development there are between the bearing surfaces of adjacent bearing arms connecting arches provided as coupling means; all bearing surfaces together with the coupling means form a closed structure. These coupling means ensure that the individual bearing surfaces cannot be moved independently from another, but that the movement of one bearing surface transfers to adjacent bearing surfaces. Advantageously, the coupling elements are defined as springs which for instance can be OMEGA-shaped flat springs or undulated springs. In the OMEGA-shaped design the opening of the OMEGA is directed outwardly and both its feet are connected with the two bearing surfaces of adjacent bearing plates. To be able to cancel the rigidity, the bent off edge regions of the outer bearing surfaces are interrupted in the region of the coupling elements. With the design of these springs, the degree of coupling is adjustable in such a way that the desired spring properties are maintained.
In a further, also advantageous, embodiment, the bearing plates are closed to form a ring. Also in this case the bearing surfaces are stepped, wherein each outer bearing surface compared with the inner bearing surface/s is at a higher level relative to the upper side of the head part from the foot part. The ring-shaped bearing surfaces are connected with each other via radial connectors, wherein these are formed in angular position. Radial connectors and/or bearing surfaces can be provided with recesses in order to improve the ventilation even further. Advantageously two ring-shaped, closed, stepped bearing surfaces connected with each other via radial connectors are provided; in a further development three ring-shaped, closed bearing surfaces connected with each other via radial connectors are provided. The form of the zing shaped bearing surfaces is circular orxe2x80x94alternativelyxe2x80x94square.
In a preferred embodiment, the bearing element is a plastic injection moulded part. The bearing element of this embodiment is simple to produce, the costs for the injection moulding tool because of the large quantity of the bearing elements do not lead to a noticeable cost increase of the individual piece. It is understood that for the production of such bearing elements with regard to their durability against mechanical loads or chemical effects high quality plastics must be used which have sufficient durability. Plastics preferably used are thermoplastic elastomers.
In order to produce a bed system with these bearing elements, these bearing elements are placed on a plate or are fixed to a lath, wherein corresponding fastening means to fasten the bearing elements are provided. In one embodiment a grid support made from intersecting support structure elements (undercrosses) is placed on the plate with fastening means for the bearing elements at the intersections. The individual undercrosses, whose number corresponds to that of the bearing elements, can be joined together by means of socket connectors.
In one embodiment, the bearing element is fixed to a plate, to a grid support placed on the plate or to a lath by means of bonding or welding; in a further embodiment by means of screws (alternatively nails or tacks) or by dowel pins. In another embodiment, the bearing element is fixed to the plate, to the grid support placed on the plate or to the laths by means of plugging into a plug-in connection or by twist locking into a twist-locking connection, wherein the latter is provided on the plate, on the grid support placed on the plate or to the lath in such number which corresponds to the number of the bearing elements provided in the top surface.
The second embodiment of a bed system, equipped with such bearing elements, besides the resolution of the top surface also has steps in the deflection, so that a greater upholstery comfort can be expected, since the bearing elements in accordance with the invention have varying heights. Thereby zones of varying deflection can be formed in a surprisingly simple manner in such a way that in the zone of minor loadingxe2x80x94for instance in the area of the head, lower leg/footxe2x80x94bearing elements without spring bodies between foot support and bearing plate are provided, wherein here the laths are set xe2x80x9chighxe2x80x9d by means of the known stepped dowel. In the zone of increased loadingxe2x80x94for instance in the region of the thighs, pelvis, trunkxe2x80x94by contrast bearing arms with spring bodies arranged between foot mount and bearing plate, and in this arrangement the laths are set xe2x80x9clowxe2x80x9d by means of the stepped dowels.
In this way, zones of differing firmness result transverse to the extension of the laths, which compensate for the differing loads in these zones. However, also within the zone region of a lath, skewness does not occur, the lath ends are at the same height, the deflections result at certain points due to the individual bearing elements. Advantageously, at least two zones are provided, one zone with bearing elements which are formed of base plate and bearing plate and one zone with bearing elements, formed of foot support, bearing body and bearing plate, wherein by means of stepped dowels, which allow a high and a low position, the first zone is arranged at the frame in a higher position and the second zone in a lower position. In these arrangements, the second zone with bearing elements with spring bodies is essentially provided in the centre of the grid, corresponding to the position of the buttocks of a reclining occupant. At either side of this second zone, a first zone with bearing elements without spring bodies is provided.
Advantageously, the frame is provided with a hinged frame part, the frame having hinges opposite each other. This allows at least one frame part to be elevated; in a further development also the second frame part is designed to be elevated. It is further advantageous to hinge a further frame part onto the elevatable frame part, which again is equipped with at least two laths with bearing elements. This frame part in a grid for a bed defines a head rest, for instance to facilitate reading. Each of the frame parts which can be elevated in relation of the base frame has furthermore at least two rows of bearing elements. Here at least one row of the bearing elements of the outermost of the elevatable frame parts have bearing elements, formed of foot support and bearing plate, whilst the other rows are provided with bearing elements, formed of foot support, spring body and bearing plate. The lower parts and/or the bearing plates and/or the spring bodies of the two embodiments are advantageously made of plastic injection-moulded parts and can also be economically produced in large quantities.